Metall aktiengeselischaft



Famed Feb. 26,1929. I 1,703,634.

, UNITED STATES PATENTVOFFICE.

EMIL PODSZUS, BERLIN-FRIEDRICHSHAGEN, GERMANY, ASSIGNOR TO HA RTSTQFF- METALL AKTIENGESELLSCHAFT (HAMETAG), F BERLIN-COPENICK, GERMANY.

PULVERIZING IROCESS.

No Drawing. Application filed April 24, 1925, Serial No.' 25,706, and in Germany April 28, 1924. I

My invention relates to processes for proerable. Thus, in the treatment of soft met- 50 ducing fine powders particularly metallic als, such as aluminum, lead, tinand the like,

powders by causing particles of the substance with an admixture of lubricant as muchas ten to. be pulverized to repeatedly collide with times the present output with the same power each other because of the action of fluid edconsumption may be obtained. Even in the dies. In the mills already provided for this case .of metals, like copper, a threefold or 55 purpose the particles are carried along in a even greater increase of output can be obclosed chamber by gas eddies moving in optained. posite directions and thus causing the par- In the practical application of my novel ticles to impinge upon each other, such as process about 1.5 gr. of olive oil is added to for instancev described and shown in my Pat- 1 kg. of copper, or 10 gnof parafiinare 0 ent No. 1,573,017 of Feb. 16, 1926. In this added to 1 kg. of aluminum or tin. The manner, the disintegration process, even of lubricant may be continuously fed into the very soft metals, can be carried to a very pulverizing mill during the operation of the great extremity. The power requiredto ebsame, or it may, be mixed with the material 'tain an extremely fine powder varies with to be ulverized, before said material is the kind of substance or metal treated. placed n the mill. I The object of the presentflnvention is to An advantage vof the continuous feed improve the above said process which I acmethod is that the contents of lubricant in 2 complish by considerably reducing the power the material to be pulverized can be better i required for the operation ofthe pulverizing regulated and consequently more easily kept 7 mill'while at the same-time increasing an outin its proper proportion. The shape of the I put many times above that obtained by theindividual particles of the pulverized matepresent method. rial is affected in a peculiar manner by the The present invention alsofienables the kind of lubricantused. Thus, the particles structure and shape of the individual pa'i'timay be ball-shaped or may have the shape cles of the 'fine powder obtained to be afof small flakes according as the one or other fected. kind of lubricant is used. If olive oil'is This I accomplish by adding to the mateadded to aluminum a powder is obtained the 7 30 rial to be pulverized a small percentage by particles of which are substantially ball- "f volume of a lubricant which spreads over shaped, whereas an admixture of paraffin the particles during'the pulverizing process will cause substantially flake-shaped partiin the form .of athm coating .orsking cles to be formed. The particular kind of v Thequantity of the oily or fatty admixparticles obtained depends upon the kind 35 ture' is preferably such that even the finest of metal, the kind of lubricant, the duration particles will became covered with an exof the pulverizing process and other factors. tremely thin coating or layer, but the coating It can be best'ascertained in" each case'by must not" be too thick as thiswould result in experiment. the particles sticking together so as to inter- If the lubricant added is undesirable in 40 fore with, or even completely stop, the procthe finished powder it can be subsequently es of disintegration. Therefore, the quan-. removed by washing, or preferably by steamtit of lubricant added must only amountto in to the required extent. I p a iew percent by volume. I The admixture may also be composed of a The lubricants employed ar'e'chiefly oils, mixture of diflerent kinds of fatty sub- 1 45 fats, wax, paraflin, stearin and oily 'substances, such as fats, oils,- wax, paraflin, Y stances, such-as turpentine, 'tetralin-and the stearin and the like. The most effective adlike. 1-

' mixture and the most favorable proportion J The increase in the efiiciency of the pulverof the same should be ascertained in each in- Y izing process is astonishing and very eonsidstance byexperiment. v

I claim 'ing the pulverizing operation a maximum of The process of pulverizing metals in a dry 2% of a fatty substance adapted to coat all state comprising causing the metal particles the metal particles with a Very fine film leavto repeatedly impinge upon each other by ing the metal particles in a dry state. 5 means of a plurality of opposed fluid cur- In testimony whereof I have aflixed my rents continually circulating Within a closed signature. space, and adding to the metal particles ,dur- DR. EMIL PODSZUS; 

